Experimental study on axial compression performance of SMA wire reinforced concrete columns under secondary loading

In order to study the axial compression performance of super-elastic shape memory alloy reinforced concrete columns under secondary loading, this paper analyzes the axial bearing capacity and deformation capacity of concrete columns under different reinforcement amounts, pre-strain levels, and different initial working pressures through the axial compression comparison test of 12 SMA confined concrete column specimens. The results show that the constraint effect of pre-strain superelastic SMA wire makes the concrete column change from brittle failure to ductile failure. The ultimate bearing capacity of concrete columns increases with the increase of SMA wire reinforcement and pre-strain. The peak deformation is greatly affected by the amount of SMA wire reinforcement, and the influence of pre-strain is limited. Different initial working pressures have little effect on the bearing capacity; the calculation results obtained by theoretical analysis are in good agreement with the experimental data. On this basis, a simplified calculation method for practical engineering is proposed.